i think i finally decided

ok guys i think i finally decided on which tuner program to go with. i think i will be going with mega squirt. is this program good to use for my NA-T swap. and what are the advantages and disadvantages of using it. sorry if this has been asked before, just trying to get some details. and also can i buy a preassembled unit or do i have to assemble it myself, and also how do i go about using a wiring harness or do i have to fabricate that also. any tips any of you have will be greatly appreciated and again i appologive if this has been asked before but the search option has disappeared. and also what items will i need to use mega squirt. any links will be good also